A well-documented problem in many countries is contaminated subsurface soil by volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPH), and/or other contaminants. Such contaminants can become sources of water contamination. For example, certain toxic VOCs can move through soil by dissolving into water passing through. Examples of such toxic VOCs include trichloroethylene (TCE), vinyl chloride, tetrachloroethylene (PCE), methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane (TCA), 1,1-dichloroethane, 1,1-dichloroethene, carbon tetrachloride, benzene, chloroform, chlorobenzenes, ethylene dibromide, and methyl tertiary butyl ether.
Many techniques have been developed for remediation of contaminated soil, groundwater, or wastewater. Example techniques include dig-and-haul, pump-and-treat, biodegradation, sparging, and vapor extraction. However, using such techniques to meet stringent clean-up standards can be costly, time-consuming, and ineffective for recalcitrant compounds.